Coding method, decoding method, coder, and decoder

ABSTRACT

A coding method, a decoding method, a coder, and a decoder are disclosed herein. A coding method includes: obtaining the pulse distribution, on a track, of the pulses to be encoded on the track; determining a distribution identifier for identifying the pulse distribution according to the pulse distribution; and generating a coding index that includes the distribution identifier. A decoding method includes: receiving a coding index; obtaining a distribution identifier from the coding index, wherein the distribution identifier is configured to identify the pulse distribution, on a track, of the pulses to be encoded on the track; determining the pulse distribution, on a track, of all the pulses to be encoded on the track according to the distribution identifier; and reconstructing the pulse order on the track according to the pulse distribution.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/617,585, filed on Feb. 9, 2015, which is a continuation of U.S.patent application Ser. No. 13/622,207, filed on Sep. 18, 2012, now U.S.Pat. No. 8,988,256. The U.S. Pat. No. 8,988,256 is a continuation ofU.S. patent application Ser. No. 12/607,723, filed on Oct. 28, 2009, nowU.S. Pat. No. 8,294,602, which is a continuation of International PatentApplication No. PCT/CN2008/070841, filed on Apr. 29, 2008. TheInternational Patent Application No. PCT/CN2008/070841 claims priorityto Chinese Patent Application No. 200710103023.5, filed on Apr. 29,2007, and Chinese Patent Application No. 200710153952.7, filed on Sep.15, 2007. The aforementioned patent applications are hereby incorporatedby reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a coding method, a decoding method, acoder, and a decoder.

BACKGROUND

In the vector coding technology, residual signals subsequent adaptivefiltering generally undergo quantization coding by using algebraiccodebooks. After the information about the position and the sign of theoptimum algebraic codebook pulse on the track is searched out, thecorresponding index value is calculated out through coding so that thedecoder can reconstruct a pulse order according to the index value. Oneof the main objectives of researching and developing the algebraiccodebook pulse coding method is to minimize the bits required by thecoding index value on the precondition of ensuring losslessreconstruction.

The Extended Adaptive Multi-Rate Wideband (AMR_WB+) coding method is analgebraic codebook pulse coding method in the conventional art.Depending on the coding rate, one to N pulses may be encoded on eachtrack. With the increase of coding pulses, the bits required forencoding such an amount of pulses also increase. For example, for atrack with M=2^(m) positions, encoding one pulse on the track requiresm+1 bits, and encoding six pulses on the track requires 6 m−2 bits. Inthe process of developing the present invention, the inventor finds thatin the algebraic pulse coding in the conventional art, a recursion-likecoding method is applied to break down a coding pulse with many pulsesinto several coding pulses with fewer pulses, thus making the codingprocess rather complex. Meanwhile, with the increase of coding pulses onthe track, the redundancy of the coding index accrues, thus tending tocause waste of coding bits.

SUMMARY

A coding method, a decoding method, a coder, and a decoder capable ofsaving coding bits effectively are disclosed in an embodiment of thepresent invention.

A coding method is disclosed according to an embodiment of the presentinvention. The coding method includes: (1) obtaining a pulsedistribution, on a track, of pulses to be encoded on the track; (2)determining a distribution identifier for identifying the pulsedistribution according to the pulse distribution; and (3) generating acoding index including the distribution identifier.

A decoding method is disclosed according to an embodiment of the presentinvention. The decoding method includes: (1) receiving a coding index;(2) obtaining a distribution identifier from the coding index, where thedistribution identifier is configured to identify a pulse distribution,on a track, of pulses encoded on the track; (3) determining the pulsedistribution, on the track, of all the pulses encoded on the track,according to the distribution identifier; and (4) reconstructing a pulseorder on the track according to the pulse distribution.

A coder is disclosed according to an embodiment of the presentinvention. The coder includes: (1) a pulse distribution obtaining unit,adapted to obtain a pulse distribution, on a track, of pulses to beencoded on the track; (2) a distribution identifier determining unit,adapted to determine a distribution identifier for identifying the pulsedistribution according to the pulse distribution obtained by the pulsedistribution obtaining unit; and (3) a coding index generating unit,adapted to generate a coding index including the distribution identifierdetermined by the distribution identifier determining unit.

A decoder is disclosed according to an embodiment of the presentinvention. The decoder includes: (1) a coding index receiving unit,adapted to receive a coding index; (2) a distribution identifierextracting unit, adapted to obtain a distribution identifier from thecoding index received by the coding index receiving unit, where thedistribution identifier is configured to identify a pulse distribution,on a track, of pulses encoded on the track; (3) a pulse distributiondetermining unit, adapted to determine the pulse distribution on thetrack, of all the pulses encoded on the track, according to thedistribution identifier obtained by the distribution identifierextracting unit; and (4) a pulse order reconstructing unit, adapted toreconstruct a pulse order on the track, according to the pulsedistribution determined by the pulse distribution determining unit.

In the embodiments of the present invention, the coding index may carrya distribution identifier for identifying the pulse distribution, andbreak down a coding pulse with many pulses into several coding pulseswith fewer pulses. In this way, a coding index includes lessinformation, and therefore, the coding index requires fewer bits, thussimplifying the coding process, reducing coding redundancy, and savingcoding bits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a coding method according to a first embodimentof the present invention;

FIG. 2 shows a structure of a 5-pulse coding index according to thefirst embodiment of the present invention;

FIG. 3 shows a structure of an XX(N) tree in the case of

=3 according to a second embodiment of the present invention;

FIG. 4 is a flowchart of a coding method according to a third embodimentof the present invention;

FIG. 5 shows a structure of a 6-pulse coding index according to thethird embodiment of the present invention;

FIG. 6 shows a structure of a 5-pulse coding index according to thethird embodiment of the present invention;

FIG. 7 shows a structure of an X(N) tree in the case of N=2 according toa fourth embodiment of the present invention;

FIG. 8 shows a structure of an X(N) tree in the case of N=3 according tothe fourth embodiment of the present invention;

FIG. 9 is a flowchart of a coding method according to a fifth embodimentof the present invention;

FIG. 10 is a flowchart of a decoding method according to a seventhembodiment of the present invention;

FIG. 11 is a flowchart of a decoding method according to a ninthembodiment of the present invention;

FIG. 12 is a flowchart of a decoding method according to an eleventhembodiment of the present invention;

FIG. 13 shows a logical structure of a coder according to a thirteenthembodiment of the present invention;

FIG. 14 shows a logical structure of a coder according to a fourteenthembodiment of the present invention;

FIG. 15 shows a logical structure of a coder according to a fifteenthembodiment of the present invention;

FIG. 16 shows a logical structure of a decoder according to a sixteenthembodiment of the present invention;

FIG. 17 shows a logical structure of a decoder according to aseventeenth embodiment of the present invention; and

FIG. 18 shows a logical structure of a decoder according to aneighteenth embodiment of the present invention.

DETAILED DESCRIPTION

The methods and the apparatuses under the present invention are detailedbelow.

Embodiment 1

A coding method is disclosed in the first embodiment of the presentinvention. As shown in FIG. 1, the coding method includes the followingsteps:

A1: Statistics about the positions of the pulses to be encoded on atrack are collected to obtain the distribution of positions of pulses onthe track.

The total quantity of pulses to be encoded on the same track generallydepends on the code rate. In this embodiment, pulse_num represents thetotal quantity of pulses to be encoded on the same track, and it isassumed that pulse_num=

and a pulse distribution vector Q(

) indicates how each position of the pulse is distributed on the track,and Q(

)={q(0), q(1), . . . , q(

−1)}, where q(h) is a serial number of the position for the (h+1)^(th)pulse on the track, hε[0,

−1], q(h)ε[0, M−1], and M represents the total quantity of positions onthe track, for example, M=8, M=16, and so on.

Besides, a pulse to be encoded may carry a sign, namely, a positive signor a negative sign. In this case, the pulse sign information of eachpulse needs to be obtained at the time of collecting statistics aboutthe pulses to be encoded on the track. In this embodiment, the pulsesign information of each pulse is represented by a pulse sign vector,namely, SS(

)={ss(0), ss(1), . . . , ss(

−1)}, where ss(h) represents the pulse sign for the (h+1)^(th) pulse,and is known as a sign index of the q(h) pulse. The pulse signrepresented by ss(h) may be a positive value or a negative value. Asimple coding mode is generally applied, namely, ss(h)=0 represents apositive pulse and ss(h)=1 represents a negative pulse. Nevertheless,for the pulses to be encoded, pulse signs are not a mandatory feature.As specifically required, a pulse may have only the position feature andthe quantity feature. In this case, it is not necessary to collectstatistics about the pulse sign information.

Evidently, a one-to-one corresponding relation may exist between Q(

) and SS(

).

After the parameters such as Q(

) and SS(

) of the pulses to be encoded are obtained through statistics, theparameters may be encoded into indices, and a corresponding relation isestablished between the parameter and the index so that the decoder canrecover a parameter according to the corresponding index. In the presentinvention, a corresponding relation may be expressed in two modes. Oneis a calculation relation denoted by an algebraic mode, where the coderperforms forward calculation for the parameter to obtain the index, andthe decoder performs reverse calculation for the index to obtain theparameter; and the other is a query relation denoted by a mapping mode,where a mapping table that correlates the parameter with the index needsto be stored in both the coder and the decoder. A corresponding relationmay be selected among the foregoing two corresponding relationsaccording to the characteristics of the parameter. Generally, when thedata quantity is large, the corresponding relation denoted by acalculation relation is preferred because it saves the storage space ofthe coder and the decoder.

A2: The distribution index (also referred to as distribution identifier)I4 is determined. The I4 may be calculated in this way: All possibledistributions of the positions of all the pulses on the track arepermuted in a set order, supposing that the current quantity of pulsesis

, and the permuting number in the permutation serves as a distributionindex I4 indicative of the distribution.

The “set order” may be understood as an order of all possible Q(

) values determined by the coder and the decoder according to the samesequencing calculation rule.

The total quantity of possible values of the pulse distribution vectorQ(

) is WQ(

)=C_(PPT) ^(N), where PPT=M+

−1, and C refers to calculating the combination function. Each I4corresponds to a pulse distribution in the WQ(

).

Generally, the WQ(

) is a large data quantity. Therefore, a calculation relation ispreferred as a corresponding relation with the distribution index I4.Nevertheless, it is also practicable to express the correspondingrelation through a query relation. Evidently, WQ(

) is the total quantity of all possible values of I4. If the value of I4starts from 0, I4ε[0, WQ(

)−1].

A3: A coding index, namely, Index(

), is generated. The Index(

) includes information about the distribution index I4.

The I4 may be placed into the coding index in any mode identifiable tothe decoder, for example, by placing the I4 into the positions thatstart from a set position of the coding index, which is the simplestmode.

Nevertheless, in the case that the pulse being encoded includes a sign,the Index(

) also needs to carry information about the sign index, namely, ss(h),of each pulse. The pulse sign vector SS(

) may be simply placed as a field with a length of

into a fixed position of the coding index, for example, at the end ofthe coding index.

To sum up, a mode of constructing the Index(

) may be:

Index(

)=I4×

+ss(0)×

+ss(1)×

+ . . . +ss(N−1).

It is easily understandable that the mode of constructing a coding indexdescribed above is only an example of this embodiment. In practice, itis easy to derive other modes of constructing a coding index structurefrom the basic information about the coding index structure, forexample, by swapping or recombining the index positions. The mode ofconstructing a coding index does not constitute any limitation to theembodiments of the present invention.

Examples are given below in order to further facilitate theunderstanding of the mode of constructing a coding index in the firstembodiment of the present invention, supposing that the total quantityof positions on the track is M=16.

Example 1

=5 pulses with signs are encoded. FIG. 2 shows the structure of thecoding index.

The coding index, namely, Index(5), occupies 19 bits in total. That is,Index(5)ε[0, 2¹⁹−1]. The coding value range of the Index(5) in FIG. 2 ishexadecimal. In this embodiment, the value preceded by “0x” means thatthe value is hexadecimal. Other values are decimal unless otherwisespecified.

Five sign indices, namely, ss(0)˜ss(4), occupy five bits at the end.

In FIG. 2, a space of I4 bits is available to the I4. Therefore, thecoding space length available to the I4 is 2¹⁴=16384, which is enoughbecause WQ(5)=C¹⁶⁺⁵⁻¹ ⁵=15504.

Example 2

=4 pulses with signs are encoded. The structure of the coding index isas follows:

The coding index, Index(4), occupies 16 bits in total. That is,Index(4)ε[0, 2¹⁶−1].

Four sign indices, namely, ss(0)˜ss(3), occupy four bits at the end.

A space of I2 bits is available to the I4. Therefore, the coding spacelength available to the I4 is 2¹²=4096, which is enough becauseWQ(4)=C¹⁶⁺⁴⁻¹ ⁴=3876.

Example 3

=3 pulses with signs are encoded. The structure of the coding index isas follows:

The coding index, Index(3), occupies I3 bits in total. That is,Index(3)ε[0, 2¹³−1].

Three sign indices, namely, ss(0)˜ss(2), occupy three bits at the end.

A space of 10 bits is available to the I4. Therefore, the coding spacelength available to the I4 is 2¹⁰=1024, which is enough becauseWQ(3)=C¹⁶⁺³⁻¹ ³=816.

Embodiment 2

A coding method is provided in the second embodiment. A method forcalculating a distribution index I4 is provided in this embodiment, thusmaking it easy to determine the corresponding relation between I4 andthe distribution of pulses on the track through algebraic calculation,where the distribution is Q(

)={q(0), q(1), . . . , q(

−1)}.

The following Q(

) sequencing calculation rule is provided in this embodiment.

The Q(

) varies with the value combination included in it. Therefore, serialnumbers of the positions included in Q(

) may be permuted, supposing:

q(0)≦q(1)≦ . . . ≦q(

−1), or q(0)≧q(1)≧ . . . ≧q(

−1),

-   -   where the equal means that the position of the pulse is        repeatable. Supposing q(0)≦q(1)≦ . . . ≦q(        −1), q(0)ε[0, M], q(h)ε[q(h−1), M], where M is the total        quantity of positions on the track. All possible values of Q(        ) are ordered from a smaller value to a greater value or from a        greater value to a smaller value after the values in each        dimensions of the Q(        ) are compared.

If they are ordered from a smaller value to a greater value and theordered Q(

) are numbered, with the starting serial number being 0, then:

${{I\; 4} = {C_{PPT}^{} - C_{{PPT} - {q{(0)}}}^{} + {\sum\limits_{h = 1}^{ - 1}\; \left\lbrack {C_{{PPT} - h - {q{({h - 1})}}}^{ - h} - C_{{PPT} - h - {q{(h)}}}^{ - h}} \right\rbrack}}},$

-   -   where C refers to calculating the combination function, and Σ        refers to summing.

The foregoing formula may be interpreted as follows:

-   -   C_(PPT) ^(N)−C_(PPT-q(0)) ^(N) refers to the total quantity of        Q(        ) when the first pulse is located before q(0);    -   C_(PPT-1-q(0)) ^(N-1)−C_(PPT-1-q(1)) ^(N-1) refers to the total        quantity of Q(        ) when the first pulse is located at q(0) and the second pulse        is located before q(1); and    -   C_(PPT-h-q(h-1)) ^(N-h)−C_(PPT-h-q(h)) ^(N-h) is interpreted by        analogy.

It should be noted that the foregoing formula is only an exemplarycalculation relation between I4 and Q(

). Depending on the same sequencing rule, the calculation relation mayalso be expressed in other algebraic modes equivalently. If a differentsequencing rule is applied, similar calculation relations may also bedesigned. The mode of expressing the calculation relation does notconstitute any limitation to the embodiments of the present invention.

To make the foregoing I4 calculation method clearer, a relative positionvector of pulses is assumed: XX(

)={xx(1), xx(2), . . . , xx(

)}. The following one-to-one corresponding relation exists between XX(

) and Q(

):

xx(1)=q(0); and

xx(i)=q(i−1)−q(i−2).

-   -   where xx(i) represents a relative position relation between the        position of the ith pulse and the position of the (i−1)th pulse,        and iε[1,        ]. The XX(        ) can construct an        -layer tree that includes all possible values of Q(        ). The depth of the tree is        +1, and the sub-node on the ith layer represents the relative        position value xx(i) of the ith pulse. The values of xx(i) are        arranged from left to right and from a smaller value to a        greater value. The end nodes are encoded from left to right at        the bottom (namely, end nodes) of the tree. Each path from an        end node to a root node corresponds to a value of XX(        ). Therefore, the code of each end node is the distribution        index I4 indicative of the corresponding Q(        ) value.

Given below is an example. Supposing M=16 and

=3 (M is the total quantity of positions on the track), the treestructure is shown in FIG. 3, and the formula for calculating thedistribution index is:

I4(3)=C ₁₈ ³ −C _(18-q(0)) ³ +C _(17-q(0)) ² −C _(17-q(1)) ² C_(16-q(1)) ¹ −C _(16-q(2)) ¹.

If the value of

is different, the corresponding tree structure is similar, and theformula for calculating the I4 can be deduced and is not repeated hereany further.

A method for obtaining a distribution index I4 through a calculationrelation is disclosed in this embodiment. Because the data quantityoccupied by the I4 in the coding index is large, the calculation methodin this embodiment minimizes the storage load of the coder and thedecoder. The I4 is encoded continuously in a strict one-to-one relationwith Q(

), thus making the best of the coding bits and avoiding waste.

Embodiment 3

A coding method is disclosed in the third embodiment. The thirdembodiment differs from the first embodiment in that: The thirdembodiment regards the coding process in the first embodiment as a firstcoding mode, a coding mode is selected among options of the first codingmode first, and then pulses are encoded in the selected coding mode. Asshown in FIG. 4, a coding process in this embodiment includes thefollowing steps.

B1: The total quantity (

) of pulses to be encoded on the same track is determined.

The value of

generally depends on the coding rate.

B2: A coding mode is selected according to the value of

. Coding modes include a first coding mode. Depending on the selectionresult, the process proceeds to step B3 or step B4.

The coding mode described in the first embodiment is called a firstcoding mode in this embodiment. Optional coding modes include not onlythe first coding mode, but also other coding modes such as AMR_WB+ inthe conventional art. A second coding mode, which is optional, isdisclosed in this embodiment.

The coding mode may depend on the determined

value. For example, for some

values, the first coding mode is applied; and for other

values, the second coding mode is applied. Researches reveal that thefirst coding mode is preferred when the value of

is 3, 4, or 5.

B3: The result of selecting the coding mode is judged. If it isdetermined that the first coding mode is selected, the pulses areencoded in the first coding mode.

The specific coding process is similar to the description in the firstembodiment, namely, steps A1, A2, and A3 in the first embodiment.

B4. The result of selecting the coding mode is judged. If it isdetermined that the second coding mode is selected, the pulses areencoded in the second coding mode. The second coding mode may includethe following steps.

B41: Statistics about the positions of the pulses to be encoded on atrack are collected to obtain the quantity of positions with a pulse,pulse distribution of the positions with a pulse on the track, and thequantity of pulses in each position with a pulse.

Similar to step A1 in the first embodiment, a pulse position vector,namely, P(N)={p(0), p(1), . . . , p(N−1)}, represents the distributionof the positions with a pulse on the track; a position sign vector,namely, S(N)={s(0), s(1), . . . , s(N−1)}, represents the pulse signinformation of each position with a pulse; and the quantity of thepositions with a pulse is obtained. In this embodiment, a pulse quantityvector, namely, SU(N)={su(0), su(1), . . . , su(N−1)}, represents thequantity of pulses in each position with a pulse, where su(n) representsthe quantity of pulses in the p(n) position. Evidently, su(0)+su(1)+ . .. +su(N−1)=

Evidently, in this embodiment, a one-to-one corresponding relationexists between P(N), SU(N), and S(N).

After the parameters such as N, P(N), SU(N), and S(N) of the pulses tobe encoded are obtained through statistics, the parameters need to beencoded into indices, and a corresponding relation is establishedbetween the parameter and the index so that the decoder can recover aparameter according to the corresponding index.

B42: The first index I1 is determined according to the quantity (namely,pos_num=N) of positions with a pulse. The first index I1 corresponds toall possible distributions of the positions with a pulse on the trackwhen the pos_num is the same.

The pos_num value (N) fluctuates mildly. Therefore, the correspondingrelation with the first index I1 may be expressed by either acalculation relation or a query relation. At the time of establishing acorresponding relation between pos_num and I1, this correspondingrelation may be assumed as a one-to-one corresponding relation.Nevertheless, when the pos_num has other values, the index of otherparameters requires fewer bits. Such pos_num values may use one I1jointly, and are distinguished through an extra flag bit.

The pos_num value (N) decides the total quantity of all possible P(N)values, and the total quantity is W(N)=C_(M) ^(N), where C refers tocalculating the combination function. Therefore, one I1 corresponds toW(N) possible P(N), where W(N) is a natural number.

B43: The second index I2 is determined according to the distribution ofthe positions with a pulse, where the distribution is expressed by P(N).The second index I2 indicates the instance of distribution correspondingto the distribution of the current positions with a pulse among allpossible distributions corresponding to the first index I1.

The total quantity of all possible P(N) values is W(N)=C_(M) ^(N). TheW(N) is a large data quantity. Therefore, a calculation relation ispreferred as a corresponding relation with the second index I2.Nevertheless, it is also practicable to express the correspondingrelation through a query relation. Evidently, W(N) is the total quantityof all possible values of I2. If the value of I2 starts from 0, 12ε[0,W(N)−1].

B44: The third index I3 is determined according to SU(N) whichrepresents the quantity of pulses in each position with a pulse.

The SU(N) is a vector whose dimension is the same as the dimension ofP(N), but is limited to su(0)+su(1)+ . . . +su(N−1)=

, where the value of

generally ranges from 1 to 6. Therefore, the corresponding relation withthe third index I3 may be expressed by either a calculation relation ora query relation. Moreover, in view of the vector form, the queryrelation is preferred in the case of high dimensions, and thecalculation relation is preferred in the case of low dimensions becauseit makes the design easier. It should be noted that in some extremecircumstances, for example, if N=1 or N=

, the SU(N) has only one possible value, which does not need to beindicated by a specific I3, and the I3 may be regarded as any value thatdoes not affect the final coding index.

B45: A coding index, namely, Index(

), is generated. The Index(

) includes information about the first index I1, the second index I2,and the third index I3.

The I1, I2, and I3 may be placed into the coding index in any modeidentifiable to the decoder, for example, by placing them into a fixedfield separately, which is the simplest mode. When the total quantity(pulse_num) of pulses to be encoded on the same track is constant, thepos_num value (N) indicated by I1 decides the range of I2 and I3,namely, decides the quantity of coding bits required by I2 and I3.Therefore, the coding index is constructed in the following mode:

(1) The first index I1 is used as a start value, and the informationabout other indices is overlaid. A value of I1 corresponds to anindependent value range of the coding index. In this way, the decodercan determine the pos_num value (N) directly according to the valuerange of the coding index.

(2) Further, in the value range of the I1 (generally corresponding to acertain field length), the I2 and the I3 may be placed in any modeidentifiable to the decoder, for example, by placing them separately,which is the simplest mode. Generally, neither I2 nor I3 can beexpressed as 2^(n) (n is an integer number). Therefore, in order to savecoding bits, I2 and I3 may be combined in the following way and placedinto the specified value range of I1:

I23=I3×W(N)+I2=I3×C _(M) ^(N) +I2.

where the coding of both I2 and I3 starts from 0, I2ε[0, C_(M) ^(N)−1],and I3ε[0, Class(N)−1], where Class(N) is the total quantity of possiblevalues of SU(N); evidently, such a mode is equivalent to dividing thevalue range of I1 into Class(N) portions, where the length of eachportion is W(N), and each portion corresponds to a distribution, namely,a SU(N) value.

(3) Nevertheless, in the case that the pulse being encoded includes asign, the Index(

) needs also to carry information about the sign index, namely, s(n), ofeach pulse. The position sign vector S(N) may be simply placed as afield with a length of N into a fixed position of the coding index, forexample, at the end of the coding index.

To sum up, a mode of constructing the Index(

) may be:

Index(

)=I1+I23×

+s(0)×

+s(1)×

+ . . . +s(

−1).

It is easily understandable that the mode of constructing a coding indexdescribed above is only an example of this embodiment. In practice, itis easy to derive other modes of constructing a coding index structurefrom the basic information about the coding index structure, forexample, by swapping or recombining the index positions. The mode ofconstructing a coding index does not constitute any limitation to theembodiments of the present invention.

For any quantity of pulses to be encoded, the coding logics provided inthe second coding mode may be applied uniformly, thus avoiding increaseof the coding index redundancy of the recursive mode applied in AMR_WB+,and ensuring a high utilization ratio of the coding bits. Meanwhile, itis not necessary to encode multiple pulses in the same positionseparately. Instead, the positions of pulses are merged before coding,thus saving coding bits. With the increase of the pulses to be encodedon the track, the probability of overlaying pulse positions alsoincreases, and the merits of the embodiments of the prevent inventionare more noticeable.

Examples are given below in order to further facilitate theunderstanding of the mode of constructing a coding index in the secondcoding mode. Supposing that the total quantity of positions on the trackis M=16 and the quantity of positions with a pulse is pos_num, and thepos_num is in a one-to-one corresponding relation with the first indexI1:

Example 1

=6 Pulses with Signs are Encoded. FIG. 5 Shows the Structure of theCoding Index.

The coding index, namely, Index(6), occupies 21 bits in total. That is,Index(6)ε[0, 2²¹−1]. FIG. 5 shows the quantity of bits occupied bydifferent portions of Index(6) when the pos_num value varies. To put itmore clearly, I1(N), I2(N), I3(N), and I23(N) are used to represent theforegoing index when N is a specific value. The I1(N) is determined in amapping mode:

-   -   I1(1)=0x1F0000, I1(2)=0x1E0000, I1(3)=0x1D0000,    -   I1(4)=0x180000, I1(5)=0x000000, I1(6)=0x100000.

FIG. 5 is described below.

(1) When six pulses are in one position, N=1, W(1)=16, I2(1)ε[0, 15],SU(1)={6}, Class(1)=1, and I3(1)=0,

-   -   and therefore, I23(1)=I2(1)ε[0, 15];    -   one sign index, namely, s(0), occupies one bit at the end; and    -   the coding space length provided by I1(1) for I23(1) is        [2²¹−I1(1)]/2¹=32768, which is obviously enough.

(2) When six pulses are in two positions, N=2, W(2)=120, I2(2)ε[0, 119],SU(2)={5, 1}, {4, 2}, {3, 3}, {2, 4}, {1, 5}; Class(2)=5, and I3(2)ε[0,4],

-   -   and therefore, I23(2)=I3(2)×120+I2(2)ε[0, 599];    -   two sign indices, namely, s(0) and s(1), occupy two bits at the        end; and    -   the coding space length provided by I2(2) for I23(2) is        [I1(1)−I1(2)]/22=16384, which is obviously enough.

(3) When six pulses are in three positions, N=3W(3)=560, I2(3)ε[0, 559],SU(3)={4, 1, 1}, {1, 4, 1}, {1, 1, 4}, {3, 2, 1}, {3, 1, 2}, {2, 3, 1},{2, 1, 3}, {1, 3, 2}, {1, 2, 3}, {2, 2, 2}; Class(3)=10, and I3(3)ε[0,9],

-   -   and therefore, I23(3)=I3(3)×560+I2(3)ε[0, 5599];    -   three sign indices, namely, s(0)-s(2), occupy three bits at the        end; and    -   the coding space length provided by I2(3) for I23(3) is        [I1(2)−I1(3)]/2³=8192, which is obviously enough.

(4) When six pulses are in four positions, N=4, W(4)=1820, I2(4)ε[0,1819], SU(4)={3, 1, 1, 1}, {1, 3, 1, 1}, {1, 1, 3, 1}, {1, 1, 1, 3}, {2,2, 1, 1}, {2, 1, 2, 1}, {2, 1, 1, 2}, {1, 2, 2, 1}, {1, 2, 1, 2}, {1, 1,2, 2}; Class(4)=10, and I3(4)ε[0, 9],

-   -   and therefore, I23(4)=I13(4)×1820+I2(4)ε[0, 18199];    -   four sign indices, namely, s(0)-s(3), occupy four bits at the        end; and    -   the coding space length provided by I2(4) for I23(4) is        [I1(3)−I1(4)]/24=20480, which is obviously enough.

(5) When six pulses are in five positions, N=5, W(5)=4368, I2(5)ε[0,4367], SU(5)={2, 1, 1, 1, 1}, {1, 2, 1, 1, 1}, {1, 1, 2, 1, 1}, {1, 1,1, 2, 1}, {1, 1, 1, 1, 2}; Class(5)=5, and I3(5)ε[0, 4],

-   -   and therefore, I23(5)=I3(5)×4368+I2(5)ε[0, 21839];    -   five sign indices, namely, s(0)-s(4), occupy five bits at the        end; and    -   the coding space length provided by I2(5) for I23(5) is        [I1(6)−I1(5)]/25=32768, which is obviously enough.

(6) When six pulses are in six positions, N=6, W(6)=8008, I2(6)ε[0,8007], SU(6)={1, 1, 1, 1, 1, 1}, Class(6)=1, and I3(6)=0,

-   -   and therefore, I23(6)=I2(6)ε[0, 8007];    -   six sign indices, namely, s(0)-s(5), occupy six bits at the end;        and    -   the coding space length provided by I2(6) for I23(6) is        [I1(4)−I1(6)]/2⁶=8192, which is obviously enough.

Example 2

=5 pulses with signs are encoded. FIG. 6 shows the structure of thecoding index.

The coding index, Index(5), occupies 19 bits in total. That is,Index(5)ε[0, 2¹⁹−1]. FIG. 6 shows the quantity of bits occupied bydifferent portions of Index(5) when the pos_num value varies. The I1(N)is determined in a mapping mode:

-   -   I1(1)=0x78000, I1(2)=0x70000, I1(3)=0x60000,    -   I1(4)=0x40000, I1(5)=0x00000.

The detailed analysis on FIG. 6 is similar to that on FIG. 5, and is notrepeated here any further.

Example 3

=4 pulses with signs are encoded.

The coding index, Index(4), occupies 16 bits in total. That is,Index(4)ε[0, 2¹⁶−1]. The figure shows the quantity of bits occupied bydifferent portions of Index(4) when the pos_num value varies. The I1(N)is determined in a mapping mode:

-   -   I1(1)=0xE000, I1(2)=0xC000, I1(3)=0x8000, I1(4)=0x0000.

Example 4

=3 pulses with signs are encoded.

The coding index, Index(3), occupies 13 bits in total. That is,Index(3)ε[0, 2¹³−1].

The figure shows the quantity of bits occupied by different portions ofIndex(3) when the pos_num value varies. The I1(N) is determined in amapping mode:

-   -   I1(1)=0x1C00, I1(2)=0x1800, I1(3)=0x0000.

Example 5

=2 pulses with signs are encoded.

The coding index, Index(2), occupies 9 bits in total. That is,Index(2)ε[0, 2⁹−1]. The figure shows the quantity of bits occupied bydifferent portions of Index(2) when the pos_num value varies. The I1(N)is determined in a mapping mode:

-   -   I1(1)=0x1E0, I1(2)=0x000.

Example 6

=1 pulse with a sign is encoded.

The coding index, Index(1), occupies 5 bits in total. That is,Index(1)ε[0, 2⁵−1]. Considering N≡1, the Index(1) includes only indexI23(1)=I2(1) and s(0) which is a sign index of p(0).

Embodiment 4

A coding method is disclosed in the fourth embodiment. Morespecifically, a method for calculating the second index I2 in the secondcoding mode is provided in this embodiment, thus making it easy todetermine the corresponding relation between I2 and the distribution ofthe positions with a pulse on a track through algebraic calculation,where the distribution is P(N)={p(0), p(1), . . . , p(N−1)}.

In this embodiment, the method of calculating I2 is: All possible P(N)values are permuted in a set order, where N is the quantity of thepositions with a pulse corresponding to the first index I1; thepermuting number in the permutation serves as a second index I2indicative of the distribution.

The “set order” may be understood as an order of all possible P(N)values determined by the coder and the decoder according to the samesequencing calculation rule. The following sequencing calculation ruleis provided in this embodiment:

The P(N) varies with the value combination included in it. Therefore,serial numbers of the positions included in P(N) may be permuted,supposing:

-   -   p(0)<p(1)< . . . <p(N−1), or p(0)>p(1)> . . . >p(N−1).

Supposing p(0)<p(1)< . . . <p(N−1), p(0)ε[0, M−N], p(n)ε[p(n−1)+1,M−N+n], where M is the total quantity of positions on the track. Allpossible values of P(N) are ordered from a smaller value to a greatervalue or from a greater value to a smaller value after the values ineach dimensions of the P(N) are compared.

If they are ordered from a smaller value to a greater value and theordered P(N) values are numbered, with the starting serial number being0, then:

${{I\; 2} = {C_{M}^{N} - C_{M - {p{(0)}}}^{N} + {\sum\limits_{n = 1}^{N - 1}\left\lbrack {C_{M - {p{({n - 1})}} - 1}^{N - n} - C_{M - {p{(n)}}}^{N - n}} \right\rbrack}}},$

-   -   where C refers to calculating the combination function, and Σ        refers to summing.

The foregoing formula may be interpreted as follows:

-   -   C_(M) ^(N)−C_(M-p(0)) ^(N) refers to the total quantity of P(N)        when the first pulse is located before p(0);    -   C_(M-p(0)-1) ^(N-1)−C_(M-p(1)) ^(N-1) refers to the total        quantity of P(N) when the first pulse is located at p(0) and the        second pulse is located before p(1); and    -   C_(M-p(n-1)-1) ^(N-n)−C_(M-p(n)) ^(N-n) is interpreted by        analogy.

It should be noted that the foregoing formula is only an exemplarycalculation relating 14 to Q(N). Depending on the same sequencing rule,the calculation relation may also be expressed in other algebraic modesequivalently. If a different sequencing rule is applied, similarcalculation relations may also be designed. The mode of expressing thecalculation relation does not constitute any limitation to theembodiments of the present invention.

To make the foregoing I2 calculation method clearer, a relative positionvector of pulses is assumed: X(N)={x(1), x(2), . . . , x(N)}. Thefollowing one-to-one corresponding relation exists between X(N) andP(N):

x(1)=p(0); and

x(i)=p(i−1)−p(i−2).

where x(i) represents a relative position relation between the ithposition with a pulse and the (i−1)th position with a pulse, iε[1, N].The X(N) can construct an N-layer tree that includes all possible valuesof P(N). The depth of the tree is N+1, and the sub-node on the ith layerrepresents the relative position value x(i) of ith position with pulse.The values of x(i) are arranged from left to right and from a smallervalue to a greater value. The end nodes are encoded from left to rightat the bottom (namely, end nodes) of the tree. Each path from an endnode to a root node corresponds to a value of X(N). Therefore, the codeof each end node is the second index I2 indicative of the correspondingP(N) value.

In the examples given below, it is assumed that the total quantity ofpositions on the track is M=16.

Example 1

The quantity of the positions with a pulse, namely, pos_num, is n=2, andFIG. 7 shows the tree structure.

$\begin{matrix}{{I\; 2(2)} = {C_{16}^{2} - C_{16 - {x{(1)}}}^{2} + C_{16 - {x{(1)}} - 1}^{1} - C_{16 - {\lbrack{{x{(1)}} + {x{(2)}}}\rbrack}}^{1}}} \\{= {C_{16}^{2} - C_{16 - {p{(0)}}}^{2} + C_{16 - {p{(0)}} - 1}^{1} - C_{16 - {p{(1)}}}^{1}}}\end{matrix}$

Example 2

The quantity of the positions with a pulse, namely, pos_num, is n=3, andFIG. 8 shows the tree structure.

$\begin{matrix}{{I\; 2(3)} = {C_{16}^{3} - C_{16 - {x{(1)}}}^{3} + C_{16 - {x{(1)}} - 1}^{2} - C_{16 - {\lbrack{{x{(1)}} + {x{(2)}}}\rbrack}}^{2} +}} \\{{C_{16 - {\lbrack{{x{(1)}} + {x{(2)}}}\rbrack} - 1}^{1} - C_{16 - {\lbrack{{x{(1)}} + {x{(2)}} + {x{(3)}}}\rbrack}}^{1}}} \\{= {C_{16}^{3} - C_{16 - {p{(0)}}}^{3} + C_{16 - {p{(0)}} - 1}^{2} - C_{16 - {p{(1)}}}^{2} + C_{16 - {p{(1)}} - 1}^{1} - C_{16 - {p{(2)}}}^{1}}}\end{matrix}$

When the value of N is 4, 5, or 6, the corresponding tree structure issimilar, and the formula for calculating the I2 can be deduced and isnot repeated here any further.

A method for obtaining a second index I2 through a calculation relationis disclosed in this embodiment. Because the data quantity occupied bythe I2 in the coding index is large, the calculation method in thisembodiment minimizes the storage load of the coder and the decoder. TheI2 is encoded continuously in a strict one-to-one relation with P(N),thus making the best of the coding bits and avoiding waste.

The merits of the coding index construction mode in the first codingmode and the second coding mode are given below. In theory, on theprecondition that the total quantity (pulse_num) of the pulses to beencoded on the same track is constant, the quantity of all possiblepermutations of all pulses on the track is the minimum value range ofthe coding index, and the corresponding quantity of coding bits is atheoretic lower limit. When the quantity of permutations is 2^(n) (n isan integer), the theoretic lower limit of the quantity of coding bits isan integer; when the quantity of permutations is not 2^(n) (n is aninteger), the theoretic lower limit of the quantity of coding bits is adecimal fraction. In this case, certain coding redundancy exists. Whenthe total quantity of positions on the track is M=16, with differentvalues of pulse_num, a comparison is made between the theoretic lowerlimit of the quantity of coding bits, and the quantity of coding bitsrequired in the AMR_WB+ coding mode, and the quantity of bits requiredby the coding index construction mode in the first coding mode and thesecond coding mode, as shown in Table 1:

TABLE 1 Required bits Total First Second permuta- Theoretic codingcoding

tions lower limit AMR_WB+ mode mode 1 32 5 5 5 5 2 512 9 9 10 9 3 547212.4179 13 13 13 4 44032 15.4263 16 16 16 5 285088 18.1210 20 19 19 61549824 20.5637 22 22 21

Table 1 reveals that: The coding index construction mode of the secondcoding mode reaches the theoretic lower limit when the theoretic lowerlimit is an integer, and reaches 1 plus the integer part of thetheoretic lower limit when the theoretic lower limit is a decimalfraction. When

is 3, 4, or 5, the first coding mode has a coding bit length equal tothat of the second coding mode. In the case of high code rates, both ofsuch coding modes provide a coding efficiency higher than that of theAMR_WB+, namely, can save more bits.

With respect to calculation complexity, by using all the test orders inthe reference codes of the AVS-M mobile audio standard as test objects,a comparison of operation time is made between the AMR_WB+, the firstcoding mode, and the second coding mode (all sample spaces aretraversed, including the coding process and the decoding process, thefirst coding mode is the calculation mode provided in the secondembodiment, the second coding mode is the calculation mode provided inthe fourth embodiment, and the decoding mode is the corresponding modeprovided in the subsequent embodiments), as shown in Table 2:

TABLE 2 Operation time (computer clock period) First Coding SecondCoding

AMR_WB+ mode mode 1 134 38.78 5 2 168 155.9 9 3 274 278.3 13 4 480 356.516 5 633 475.6 19 6 1080 22 21

Table 2 reveals that: The first coding mode involves lower operationcomplexity in most circumstances, and the operation complexity of thesecond coding mode is equivalent to that of the AMR_WB+. Table 1 andTable 2 reveal that: By using the first coding mode and the secondcoding mode, the low calculation complexity of the first coding mode isexerted when

is 3, 4, or 5, and the low coding bit length of the second coding modeis exerted when

is another value.

Embodiment 5

A coding method is disclosed in the fifth embodiment of the presentinvention. As shown in FIG. 9, the coding method includes the followingsteps:

C1: Statistics about the pulses to be encoded on a track are collectedaccording to positions, to obtain the quantity of positions with apulse, pulse distribution of the positions with a pulse is distributedon the track, and the quantity of pulses in each position with a pulse.

The description about step C1 is similar to the description about stepB41 in the third embodiment, and is not repeated here any further.

C2: The first index I1 is determined according to the quantity (namely,pos_num=N) of the positions with a pulse. The first index I1 correspondsto all possible distributions of the positions with a pulse on the trackwhen the pos_num is the same.

The description about step C2 is similar to the description about stepB42 in the third embodiment, and is not repeated here any further.

C3: The second index I2 is determined according to the distribution ofthe pulse positions on the track, where the distribution is expressed byP(N). The second index I2 indicates the instance of distributioncorresponding to the distribution of the current position with a pulseamong all possible distributions corresponding to the first index I1.

The description about step C3 is similar to the description about stepB43 in the third embodiment, and is not repeated here any further.

C4: The third index I3 is determined according to SU(N) which representsthe quantity of pulses in each position with a pulse.

The description about step C4 is similar to the description about stepB44 in the third embodiment, and is not repeated here any further.

C5: A coding index, namely, Index(

), is generated. The Index(

) includes information about the first index I1, the second index I2,and the third index I3.

The description about step C5 is similar to the description about stepB45 in the third embodiment, and is not repeated here any further.

The relevant description about the fifth embodiment is similar to thedescription about the third embodiment (including the examples), and isnot repeated here any further.

Embodiment 6

A coding method is disclosed in the sixth embodiment. In thisembodiment, the coding logics identical to those of the fifth embodimentare applied. Specifically, a method for calculating the second index I2is provided in this embodiment, thus making it easy to determine thecorresponding relation between I2 and the distribution of the positionswith a pulse on a track through algebraic calculation, where thedistribution is P(N)={p(0), p(1), . . . , p(N−1)}. The detaileddescription is similar to that of the fourth embodiment, and is notrepeated here any further.

The decoding method disclosed herein is detailed below.

Embodiment 7

A decoding method is provided in the seventh embodiment. The decodingmethod provided in this embodiment decodes the coding index obtainedaccording to the coding method in the first embodiment. The decodingprocess is the inverse of the coding process. As shown in FIG. 10, thedecoding process includes the following steps:

D1: A coding index Index(

) is received.

D2: The distribution index I4 is extracted from the Index(

).

The process of extracting the distribution index I4 from the Index(

) may be the inverse of the process of placing the I4 into the Index(

) at the time of coding. For example, if the I4 is placed into a fixedfield, the I4 may be extracted from the field directly.

If the coded pulse is a pulse with a sign, the sign index ss(h)corresponding to each pulse needs to be extracted from the Index(

). The total quantity of bits varies with the code rate. Therefore, thedecoder may determine the total quantity of pulses encoded on the sametrack, namely, pulse_num=

, directly according to the length (quantity of bits) of the codingindex, and then extract the corresponding quantity of sign indices ss(h)from the Index(

) according to

. According to the structure of the Index(

) provided in the first embodiment, the

sign indices are located at the end of the Index(

), and therefore, each ss(h) may be extracted from the Index(

) directly.

D3: The distribution of each position of the pulses on the track, whichis expressed as Q(

), is determined according to the distribution index I4.

The decoding of the I4 is the inverse of encoding the I4. If the I4 isobtained through a calculation relation in the coding process, the samecalculation relation may be applied in the decoding process to performan inverse operation; if the I4 is obtained through a query relation inthe coding process, the same corresponding relation may be queried inthe decoding process.

D4: The pulse order on the track is reconstructed according to the Q(

), which represents the distribution of each position of the pulses onthe track.

If the pulse includes a sign, at the time of reconstructing the pulseorder on the track, the positive or negative feature of the pulse signof each pulse needs to be recovered according to the pulse signinformation carried in each sign index ss(h).

Embodiment 8

A decoding method is disclosed in the eighth embodiment. The decodinglogics applied in this embodiment are the same as those applied in theseventh embodiment. The eighth embodiment discloses a calculation methodfor decoding the distribution index I4 obtained through the codingmethod in the second embodiment. This calculation method at the decoderis the inverse of the method for calculating the I4 in the secondembodiment.

If the I4 is obtained through

${I\; 4} = {C_{PPT}^{} - C_{{PPT} - {q{(0)}}}^{} + {\sum\limits_{h = 1}^{ - 1}\; \left\lbrack {C_{{PPT} - h - {q{({h - 1})}}}^{ - h} - C_{{PPT} - h - {q{(h)}}}^{ - h}} \right\rbrack}}$

in the coding process, the following calculation process is applied atthe decoder:

-   -   (1) T[q(0)]=I4−(        −        ₋₍₀₎) is calculated from a smaller q(0) value to a greater q(0)        value, where: q(0)ε[0, M], M is the total quantity of positions        on the track,        is the total quantity of pulses encoded on the same track,        PPT=M+        −1, and C refers to calculating the combination function. The        last q(0) value that lets T[q(0)] be greater than zero is        recorded as the position v0 of the first pulse on the track.    -   (2) If        >1, T1[q(1)]=T(v0)−(        _(-v0)−        _(-q(1))) is further calculated from a smaller q(1) value to a        greater q(1) value, where q(1)ε[v0, M]; and the last q(1) value        that lets T1[q(1)] be greater than zero is recorded as the        position v1 of the second pulse on the track.    -   (3) By analogy, Th[q(h)]=T(h−1)[q(h−1)]−(        −        ) is calculated from a smaller q(h) value to a greater q(h)        value, where: q(h)ε[v(h−1), M], and hε[2,        −1]; and the last q(h) value that lets Th[q(h)] be greater than        zero is recorded as the position vh for the (h+1)^(th) pulse        (h+1 is an ordinal number) on the track.    -   (4) The decoding of the I4 is completed, and Q(        )={q(0), q(1), . . . , q(        −1)} is obtained.

Embodiment 9

A decoding method is provided in the ninth embodiment. The decodingmethod provided in this embodiment decodes the coding index obtainedaccording to the coding method in the third embodiment. The decodingprocess is the inverse of the coding process. As shown in FIG. 11, thedecoding process includes the following steps:

E1: The total quantity (

) of pulses encoded on the same track by the received coding indexIndex(

) is determined.

The decoder may determine the total quantity of pulses encoded on thesame track, namely, pulse_num=

, directly according to the length (quantity of bits) of the codingindex. Nevertheless, the decoder may also obtain the

value corresponding to the coding index in a mode agreed with theencoder (for example, by exchanging information mutually beforereceiving the coding index). This embodiment does not specify the modeof obtaining the

.

E2: A decoding mode is selected according to the value of

. Decoding modes include a first decoding mode. Depending on theselection result, the process proceeds to step E3 or step E4.

The decoding mode described in the seventh embodiment is called a firstdecoding mode in this embodiment. Optional decoding modes include notonly the first decoding mode, but also other decoding modes. Eachoptional decoding mode needs to correspond to the coding mode providedat the encoder. This embodiment provides a second decoding modecorresponding to the second coding mode described above.

In order to ensure consistency between the coding mode and the decodingmode, the decoder needs to select a decoding mode by using thecorresponding rule applied at the coder.

E3: The result of selecting the decoding mode is analyzed. If it isdetermined that the first decoding mode is selected, the pulses aredecoded in the first coding mode. The step of extracting thedistribution index from the coding index is performed.

For the specific decoding process, the description in the seventhembodiment serves as a reference.

E4: The result of selecting the decoding mode is analyzed. If it isdetermined that the second decoding mode is selected, the pulses aredecoded in the second decoding mode. The second decoding mode mayinclude the following steps:

E41: The first index I1 is extracted from the Index(

). The quantity of pulse positions, namely, pos_num, is determinedaccording to the I1.

The total quantity of bits varies with the code rate. Therefore, thedecoder may determine the total quantity of pulses encoded on the sametrack, namely, pulse_num=

, directly according to the length (quantity of bits) of the codingindex.

The process of extracting the information about each index from theIndex(

) may be the inverse of the process of combining the indices into anIndex(

) at the coder. For example, if each index is placed into a fixed fieldseparately, the index may be extracted from the field directly.

If the Index(

) is a structure that uses the I1 as a starting value and overlays otherindices as described in the third embodiment, it is appropriate toextract the I1 first, and then determine the positions of other indicesin the Index(

) according to the pos_num value (

) corresponding to the I1. In this case, considering that one I1corresponds to an independent value range of the Index(

), the decoder may judge the value range of the Index(

) among several set independent value ranges, and determine the firstindex I1 according to the starting value of such a value range.

E42: The second index I2 and the third index I3 are extracted from theIndex(

).

Like I1, the I2 and the I3 are also extracted in a process contrary tothe process of combining the I2 and the I3 into the Index(

), and can be extracted directly if they are placed independently at thecoder. If the I2 and the I3 are combined and overlaid in the codingprocess as described in the third embodiment, they can be separated inthe following steps:

(1) The combination value of I2 and I3, namely, I23, is extracted fromthe Index(

).

The position of I23 in the Index(

) may be indicated by the N value determined by the I1.

(2) The I2 and the I3 are separated in this way: I2=I23% W(N) andI3=Int[I23/W(N)]. W(N) is the total quantity of all possible P(N) in thecase of pos_num=N, and W(N)=C_(M) ^(N), where M is the total quantity ofpositions on the track, % refers to taking the remainder and Int refersto taking the integer.

E43: If the coded pulse is a pulse with a sign, the sign index s(n)corresponding to each position with a pulse needs to be extracted fromthe Index(

).

According to the structure of the Index(

) provided in the third embodiment, the N sign indices are located atthe end of the Index(

). Therefore, each s(n) may be separated from the Index(

) directly after the N value indicated by the I1 is obtained.

E44: The distribution of each position with a pulse on the track in thecase of pos_num=N is determined according to the second index I2, wherethe distribution is expressed as P(N).

The decoding of the I2 is the inverse of encoding the I2. If the I2 isobtained through a calculation relation in the coding process, the samecalculation relation may be applied in the decoding process to performan inverse operation. If the I2 is obtained through a query relation inthe coding process, the same corresponding relation may be queried inthe decoding process.

E45: The SU(N), which represents the quantity of pulses in each positionwith a pulse, is determined according to the third index I3. The rule ofdecoding the I3 is similar to the rule of decoding the I2.

E46: The pulse order on the track is reconstructed according to the P(N)and the SU(N), where: P(N) represents distribution the positions with apulse on the track, and SU(N) represents the quantity of pulses in eachposition with a pulse.

If the pulse includes a sign, at the time of reconstructing the pulseorder on the track, the positive or negative feature of the pulse signof each position with a pulse needs to be recovered according to thepulse sign information carried in each sign index s(n).

Embodiment 10

A decoding method is disclosed in the tenth embodiment. The decodinglogics applied in this embodiment are the same as those applied in theninth embodiment. The tenth embodiment discloses a calculation method inthe second decoding mode for decoding the second index I2 obtainedthrough the coding method in the fourth embodiment. This calculationmethod at the decoder is the inverse of the method for calculating theI2 in the fourth embodiment.

If the I2 is obtained through

${I\; 2} = {C_{M}^{N} - C_{M - {p{(0)}}}^{N} + {\sum\limits_{n = 1}^{N - 1}\left\lbrack {C_{M - {p{({n - 1})}} - 1}^{N - n} - C_{M - {p{(n)}}}^{N - n}} \right\rbrack}}$

in the coding process, the following calculation process is applied atthe decoder:\

(1) C_(M-1) ^(N-1), . . . , and C_(M-y0) ^(N-1) are subtracted from I2one by one.

R(y0)=I2−C _(M-1) ^(N-1) − . . . −C _(M-y0) ^(N-1),

until the I2 remainder R(y0) changes from a positive number to anegative number, where M is the total quantity of positions on thetrack, N is the quantity of the positions with a pulse, y0ε[1, M−N+1],and C refers to calculating the combination function. The p(0), namely,the serial number of the first position with a pulse on the track, isrecorded, where p(0)=y0−1.

(2) If N>1, C_(M-p(0)-1) ^(N-2), . . . , and C_(M-p(0)-y1) ^(N-2) arefurther subtracted from R[p(0)] one by one until the R[p(0)] remainderR1(x1) changes from a positive number to a negative number. The p(1),namely, the serial number of the second position with a pulse on thetrack, is recorded, where p(1)=y1−1.

(3) By analogy, C_(M-p(0)- . . . -p(n-1)-1) ^(N-n-2), . . . , andC_(M-p(0)- . . . -p(n-1)-yn) ^(N-n-2) are further subtracted fromR(n−1)[p(n−1)] one by one until the R(n−1)[p(n−1)] remainder Rn(yn)changes from a positive number to a negative number, where n≦N−1. Thep(n), namely, the serial number of the n+1 pulse position on the track,is recorded, where p(n)=yn−1.

(4) The decoding of the I2 is completed, and P(N)={p(0), p(1), . . . ,p(N−1)} is obtained.

Embodiment 11

A decoding method is provided in the eleventh embodiment. The decodingmethod provided in this embodiment decodes the coding index obtainedaccording to the coding method in the fifth embodiment. The decodingprocess is the inverse of the coding process. As shown in FIG. 12, thedecoding process includes the following steps:

F1: The coding index Index(

) is received, and the first index I1 is extracted from the Index(

). The quantity of positions with a pulse, namely pos_num, is determinedaccording to the I1.

The description about step F1 is similar to that of step E41 in theninth embodiment.

F2: The second index I2 and the third index I3 are extracted from theIndex(

).

The description about step F2 is similar to that of step E42 in theninth embodiment.

F3: If the coded pulse is a pulse with a sign, the sign index s(n)corresponding to each position with a pulse needs to be extracted fromthe Index(

).

The description about step F3 is similar to that of step E43 in theninth embodiment.

F4: The distribution of each position with a pulse on the track in thecase of pos_num=N is determined according to the second index I2, wherethe distribution is expressed as P(N).

The description about step F4 is similar to that of step E44 in theninth embodiment.

F5: The SU(N), which represents the quantity of pulses in each positionwith a pulse, is determined according to the third index I3. The rule ofdecoding the I3 is similar to the rule of decoding the I2. Thedescription about step F5 is similar to that of step E45 in the ninthembodiment.

F6: The pulse order on the track is reconstructed according to the P(N)and the SU(N), where P(N) represents the distribution of each positionwith a pulse on the track, and SU(N) represents the quantity of pulsesin each position with a pulse.

The description about step F6 is similar to that of step E46 in theninth embodiment.

Embodiment 12

A decoding method is disclosed in the twelfth embodiment. The decodinglogics applied in this embodiment are the same as those applied in theeleventh embodiment. The eighth embodiment discloses a calculationmethod for decoding the second index I2 obtained through the codingmethod in the sixth embodiment. This calculation method at the decoderis the inverse of the method for calculating the I2 in the sixthembodiment. The detailed description is similar to that of the fourthembodiment, and is not repeated here any further.

It is understandable to those skilled in the art that all or part of thesteps of the foregoing embodiments may be implemented through software,hardware, or both thereof.

The embodiments of the present invention may further include acomputer-readable storage medium for bearing or storing instructionsreadable or executable by a computer, or for storing data instructions.The program may be stored in a computer-readable storage medium such asROM/RAM, magnetic disk, and compact disk. When being executed, theprogram generated out of the instructions stored in the storage mediummay cover part or all of the steps in any embodiment of the presentinvention.

The coder and the decoder under the present invention are detailedbelow.

A coder is disclosed according to an embodiment of the presentinvention. The coder may include: (1) a pulse distribution obtainingunit, adapted to obtain the pulse distribution, on a track, of all thepulses to be encoded on the track; (2) a distribution identifierdetermining unit, adapted to determine a distribution identifier foridentifying the pulse distribution, according to the pulse distributionobtained by the pulse distribution obtaining unit; and (3) a codingindex generating unit, adapted to generate a coding index that includesthe distribution identifier determined by the distribution identifierdetermining unit.

The pulse distribution obtained by the pulse distribution obtaining unitmay include the information about the distribution of positions ofpulses on the track.

The distribution identifier determining unit may include: (1) acomparing unit, adapted to compare the pulse distribution with allpossible distributions of the pulse positions on the track; and (2) anobtaining unit, adapted to obtain a distribution identifiercorresponding to the pulse distribution compared by the comparing unit,wherein each possible distribution of the pulse positions corresponds toa distribution identifier.

The pulse distribution may include: quantity of positions with a pulse,distribution of the positions with a pulse on the track, and quantity ofpulses in each position with a pulse.

The distribution identifier may carry information about the first index,the second index, and the third index, where: (1) the first index isadapted to identify the information about all possible distributions ofthe positions with a pulse on the track when the quantity of thepositions with a pulse is the same; (2) the second index is adapted toidentify the instance of distribution corresponding to the currentposition with a pulse among all possible distributions corresponding tothe first index; and (3) the third index is adapted to identify theinformation about the quantity of pulses in each position with a pulse.

The distribution identifier determining unit may include: (1) a firstdetermining unit, adapted to determine the first index according to thequantity of positions with a pulse; (2) a second determining unit,adapted to determine the second index according to the distribution ofthe positions with a pulse on the track; and (3) a third determiningunit, adapted to determine the third index according to the quantity ofpulses in each position with a pulse.

The coder may further include: a permuting unit, adapted to: permute allthe possible distributions of the positions of the pulses on the trackin a set order with respect to the current quantity of pulses before thecomparing unit compares the pulse distribution with the informationabout all possible distributions of the positions with a pulse on thetrack, or before the second determining unit determines the second indexaccording to the distribution of the positions of pulses on the track,where the permuting number in the permutation serves as a distributionindex indicative of the distribution.

The pulse distribution obtaining unit may also obtain the pulse signinformation indicative of the positive and negative features of thepulse when obtaining the pulse distribution about how all the pulses tobe encoded on the track are distributed on the track. The distributionidentifier determining unit may also determine the pulse sign identifiercorresponding to the pulse sign information when determining thedistribution identifier. The coding index generated by the coding indexgenerating unit may also include the pulse sign identifier correspondingto each pulse.

A coder is disclosed according to an embodiment of the presentinvention. The coder may include: (1) a pulse sum determining unit,adapted to determine the total quantity of pulses to be encoded on atrack; (2) a coding mode selecting unit, adapted to select a coding modeaccording to the total quantity of pulses determined by the pulse sumdetermining unit; and (3) a coding unit, adapted to perform coding inthe coding mode selected by the coding mode selecting unit.

The coding unit may include: (1) a pulse distribution obtaining unit,adapted to obtain pulse distribution about how all the pulses to beencoded on a track are distributed on the track; (2) a distributionidentifier determining unit, adapted to determine a distributionidentifier for identifying the pulse distribution according to the pulsedistribution obtained by the pulse distribution obtaining unit; and (3)a coding index generating unit, adapted to generate a coding index thatincludes the distribution identifier determined by the distributionidentifier determining unit.

The pulse distribution may include the information about thedistribution of the positions of pulses on the track.

The distribution identifier determining unit may include: (1) acomparing unit, adapted to compare the pulse distribution with theinformation about all possible distributions of the positions of thepulses on the track; and (2) an obtaining unit, adapted to obtain adistribution identifier corresponding to the pulse distribution comparedby the comparing unit, where the information about each possibledistribution corresponds to a distribution identifier.

The coder may further include a permuting unit, adapted to: permute allpossible distributions of the positions of the pulses on the track in aset order with respect to the current quantity of pulses before thecomparing unit compares the pulse distribution with the informationabout all possible distributions of the positions of the pulses on thetrack, where the permuting number in the permutation serves as adistribution index indicative of the distribution.

The pulse distribution may include: quantity of positions with a pulse,distribution of the positions with a pulse on the track, and quantity ofpulses on each position with a pulse.

The distribution identifier may carry information about the first index,the second index, and the third index, where: (1) the first index isadapted to identify the information about all possible distributions ofthe positions with a pulse on the track when the quantity of thepositions with a pulse is the same; (2) the second index is adapted toidentify the instance of distribution corresponding to the currentposition with a pulse among all possible distributions corresponding tothe first index; and (3) the third index is adapted to identify theinformation about the quantity of pulses in each position with a pulse.

The distribution identifier determining unit may include: (1) a firstdetermining unit, adapted to determine the first index according to thequantity of the positions with a pulse; (2) a second determining unit,adapted to determine the second index according to the distribution ofthe positions with a pulse on the track; and (3) a third determiningunit, adapted to determine the third index according to the quantity ofpulses in each position with a pulse.

The coder may further include a permuting unit, adapted to: permute allpossible distributions of the positions with a pulse on the track in aset order with respect to the current quantity of pulses before thesecond determining unit determines the second index according to thedistribution of positions of the pulses on the track, where thepermuting number in the permutation serves as a distribution indexindicative of the distribution.

The pulse distribution obtaining unit may also obtain the pulse signinformation indicative of the positive and negative features of thepulse when obtaining the pulse distribution about how all the pulses tobe encoded on the track are distributed on the track. The distributionidentifier determining unit may also determine the pulse sign identifiercorresponding to the pulse sign information when determining thedistribution identifier. The coding index generated by the coding indexgenerating unit may also include the pulse sign identifier correspondingto each pulse.

A decoder is disclosed according to an embodiment of the presentinvention. The decoder may include: (1) a coding index receiving unit,adapted to receive a coding index; (2) a distribution identifierextracting unit, adapted to obtain a distribution identifier from thecoding index received by the coding index receiving unit, wherein thedistribution identifier is configured to identify the pulsedistribution, on a track, of all the pulses to be encoded on the track;(3) a pulse distribution determining unit, adapted to determine thepulse distribution, on a track, of all the pulses to be encoded on thetrack, according to the distribution identifier obtained by thedistribution identifier extracting unit; and (4) a pulse orderreconstructing unit, adapted to reconstruct the pulse order on the trackaccording to the pulse distribution determined by the pulse distributiondetermining unit.

The pulse distribution may include the information about thedistribution of positions of pulses on the track.

The pulse distribution determining unit may include:

-   -   a comparing unit, adapted to compare the distribution identifier        with the distribution identifier corresponding to all the        possible distributions of the positions of the pulses on the        track; and    -   an obtaining unit, adapted to obtain a distribution        corresponding to the distribution identifier compared by the        comparing unit, where each distribution identifier corresponds        to the information about each possible distribution.

The distribution identifier may carry information about the first index,the second index, and the third index; where

-   -   the first index is adapted to identify the information about all        possible distributions of the positions with a pulse on the        track when the quantity of positions with a pulse is the same;    -   the second index is adapted to identify the instance of        distribution corresponding to the current position with a pulse        among all possible distributions corresponding to the first        index; and    -   the third index is adapted to identify the information about the        quantity of pulses in each position with a pulse.

The pulse distribution may include: quantity of positions with a pulse,distribution of positions with a pulse on the track, and quantity ofpulses on each position with a pulse.

The distribution identifier extracting unit may include:

-   -   a first extracting unit, adapted to extract the first index from        the coding index; and    -   a second extracting unit, adapted to extract the second index        and the third index from the coding index.

The pulse distribution determining unit includes:

-   -   a first determining unit, adapted to determine the quantity of        positions with a pulse according to the first index;    -   a second determining unit, adapted to determine the distribution        of positions with a pulse on the track according to the second        index with respect to the quantity of positions with a pulse        corresponding to the first index; and    -   a third determining unit, adapted to determine the quantity of        pulses in each position with a pulse according to the third        index.

The distribution identifier extracting unit may also extract the pulsesign identifier indicative of the positive and negative features of thepulse from the coding index when extracting the distribution identifierfrom the coding index. The pulse distribution determining unit may alsodetermine the corresponding pulse sign information according to thepulse sign identifier when determining the pulse distribution accordingto the distribution identifier. The pulse order reconstructing unit mayrecover the positive or negative feature of the pulse according to thepulse sign information when reconstructing the pulse order on the track.

A decoder is disclosed according to an embodiment of the presentinvention. The decoder may include: (1) a coding index receiving unit,adapted to receive a coding index; (2) a pulse sum determining unit,adapted to determine the total quantity of pulses encoded on the trackwith respect to the coding index received by the coding index receivingunit; (3) a decoding mode selecting unit, adapted to select a decodingmode according to the total quantity of pulses determined by the pulsesum determining unit; and (4) a decoding unit, adapted to performdecoding in the decoding mode selected by the decoding mode selectingunit.

The decoding unit may include: (1) a distribution identifier extractingunit, adapted to extract the distribution identifier from the codingindex received by the coding index receiving unit, where thedistribution identifier identifies the pulse distribution about how allthe pulses to be encoded on a track are distributed on the track; (2) apulse distribution determining unit, adapted to determine the pulsedistribution about how all the pulses to be encoded on a track aredistributed on the track according to the distribution identifierextracted by the distribution identifier extracting unit; and (3) apulse order reconstructing unit, adapted to reconstruct the pulse orderon the track according to the pulse distribution determined by the pulsedistribution determining unit.

The pulse distribution may include the information about thedistribution of the positions of pulses on the track.

The pulse distribution determining unit may include: (1) a comparingunit, adapted to compare the distribution identifier with thedistribution identifier corresponding to all possible distributions ofthe positions of the pulses on the track; and (2) an obtaining unit,adapted to obtain pulse distribution corresponding to the distributionidentifier compared by the comparing unit, where each distributionidentifier corresponds to the information about a possible instance ofdistribution.

The distribution identifier may carry information about the first index,the second index, and the third index, where: (1) the first index isadapted to identify the information about all possible distributions ofthe positions with a pulse on the track when the quantity of thepositions with a pulse is the same; (2) the second index is adapted toidentify the instance of distribution corresponding to the currentposition with a pulse among all possible distributions corresponding tothe first index; and (3) the third index is adapted to identify theinformation about the quantity of pulses in each position with a pulse.

The pulse distribution may include: quantity of positions with a pulse,distribution of positions with a pulse on the track, and quantity ofpulses on each position with a pulse.

The distribution identifier extracting unit may include: (1) a firstextracting unit, adapted to extract the first index from the codingindex; and (2) a second extracting unit, adapted to extract the secondindex and the third index from the coding index.

The pulse distribution determining unit may include: (1) a firstdetermining unit, adapted to determine the quantity of positions with apulse according to the first index; (2) a second determining unit,adapted to determine the distribution of positions with a pulse on thetrack according to the second index with respect to the quantity ofpositions with a pulse corresponding to the first index; and (3) a thirddetermining unit, adapted to determine the quantity of pulses in eachposition with a pulse according to the third index.

The distribution identifier extracting unit may also extract the pulsesign identifier indicative of the positive and negative features of thepulse from the coding index when extracting the distribution identifierfrom the coding index. The pulse distribution determining unit may alsodetermine the corresponding pulse sign information according to thepulse sign identifier when determining the pulse distribution accordingto the distribution identifier. The pulse order reconstructing unit mayrecover the positive or negative feature of the pulse according to thepulse sign information when reconstructing the pulse order on the track.

The coder and the decoder under the present invention are detailed belowby reference to accompanying drawings.

Embodiment 13

A coder 10 is disclosed in the thirteenth embodiment of the presentinvention. As shown in FIG. 13, the coder includes: a first statisticunit 11, a distribution index unit 12, and an index generating unit 13,where: (1) the first statistic unit 11 is adapted to collect thestatistics of the pulses to be encoded on a track to obtain pulsedistribution about how the position of each pulse is distributed on thetrack, where the pulse distribution is represented by Q(

). When collecting the statistics of the pulse with a sign, the firststatistic unit 11 outputs the sign index information SS(

) corresponding to each pulse according to the positive or negativefeature of the pulse sign of each pulse, where the sign index indicatesthe pulse sign of the pulse corresponding to the index; (2) thedistribution index unit 12 is adapted to determine the distributionindex I4 according to the Q(

) obtained by the first statistic unit 11. The I4 is calculated in thisway: All possible distributions of the positions of all the pulses onthe track are permuted in a set order with respect to the currentquantity of pulses; and the permuting number in the permutation servesas a distribution index I4 indicative of the distribution; and (3) theindex generating unit 13 is adapted to generate a coding index Index(

) that includes the information about the distribution index I4determined by the distribution index unit 12. When encoding the pulsewith a sign, the index generating unit 13 combines the sign indexinformation SS(

) corresponding to each pulse into the Index(

).

The coding apparatus disclosed in this embodiment is applicable to thecoding methods disclosed in the first embodiment and the secondembodiment.

Embodiment 14

The fourteenth embodiment provides a coder 20. As shown in FIG. 14, thecoder includes: a first coding module 21, a second coding module 22, anda coding selecting unit 2.

The coding selecting unit 23 is adapted to: determine the total quantity(

) of pulses to be encoded on the same track, and select a coding modeaccording to

, the total quantity. In this embodiment, optional coding modes includea first coding mode and a second coding mode. Depending on the result ofselecting the coding mode, the first coding module 21 is triggered toperform coding if the first coding mode is selected; or the secondcoding module 22 is triggered to perform coding if the second codingmode is selected.

The first coding module 21 includes a first statistic unit 211, adistribution index unit 212, and an index generating unit 213. Thelogical structure of such units is the same as that of the counterpartunits in the 13th embodiment.

The second coding module 22 includes a second statistic unit 221, anindex calculating unit 222, and an index combining unit 223.

The second statistic unit 221 is adapted to: collect the statistics ofthe pulses to be encoded on a track according to positions; and outputthe quantity (N) of positions with a pulse, the P(N) and the SU(N),where P(N) represents the distribution of each position with a pulse onthe track, and SU(N) represents the quantity of pulses in each positionwith a pulse. When collecting the statistics of the pulse with a sign,the second statistic unit 221 also outputs the corresponding pulse signinformation S(N) according to the positive or negative feature of thepulse sign of each position with a pulse.

The index calculating unit 222 includes: a first index unit 2221, asecond index unit 2222, a third index unit 2223, and an index combiningunit 223.

The first index unit 2221 is adapted to output the first index I1according to the quantity (N) of the positions with a pulse. The firstindex I1 corresponds to all possible distributions of the positions witha pulse on the track when N is the same.

The second index unit 2222 is adapted to output the second index I2according to distribution of the positions with a pulse on the track,where the distribution is expressed by P(N). The second index I2indicates the instance of distribution corresponding to the distributionof the current position with a pulse among all possible distributionscorresponding to the first index.

The third index unit 2223 is adapted to output the third index accordingto the quantity of pulses in each position with a pulse, namely,according to SU(N).

The index combining unit 223 is adapted to combine the information aboutthe first index, the second index, and the third index to generate acoding index. If the pulse to be encoded includes a sign, the indexcombining unit 223 further combines the sign index information S(N)corresponding to each position with a pulse into the coding index, wherethe sign index indicates the pulse sign information of the position witha pulse corresponding to the sign index.

If the coding index structure is provided in the second coding mode inthe third embodiment, the index combining unit 223 for coding mayinclude: (1) a first combining unit 2231, adapted to output the secondindex and the third index combined into I23, namely, I23=I3×W(N)+I2,where W(N) represents the total quantity of all possible distributionsof the positions with a pulse on the track, and N represents thequantity of positions with a pulse corresponding to the first index; and(2) a second combining unit 2232, adapted to: overlay the output of thefirst combining unit 2231 with information about other indices, andoutput the coding index Index(

).

The coding apparatus disclosed in this embodiment is applicable to thecoding methods disclosed in the third embodiment and the fourthembodiment.

Embodiment 15

A coder 30 is disclosed in the fifteenth embodiment. As shown in FIG.15, the coder includes: a pulse statistic unit 31, an index calculatingunit 32, and an index combining unit 33. The pulse statistic unit 31 isadapted to: collect the statistics of the pulses to be encoded on atrack according to positions; and output the quantity (N) of positionswith a pulse, the P(N) and the SU(N), where: P(N) represents thedistribution of each position with a pulse on the track, and SU(N)represents the quantity of pulses in each position with a pulse. Whencollecting the statistics of the pulse with a sign, the pulse statisticunit 31 also outputs the corresponding pulse sign information S(N)according to the positive or negative feature of the pulse sign of eachposition with a pulse. The index calculating unit 32 includes: a firstindex unit 321, a second index unit 322, and a third index unit 323. Thefirst index unit 321 is adapted to output the first index I1 accordingto the quantity (N) of the positions with a pulse. The first index I1corresponds to all possible distributions of the positions with a pulseon the track when N is the same. The second index unit 322 is adapted tooutput the second index I2 according to distribution of positions with apulse on the track, where the distribution is expressed by P(N). Thesecond index I2 indicates the instance of distribution corresponding tothe distribution of the current position with a pulse among all possibledistributions corresponding to the first index. And the third index unit323 is adapted to output the third index according to the quantity ofpulses in each position with a pulse, namely, according to SU(N). Theindex combining unit 33 is adapted to: combine the information about thefirst index, the second index, and the third index to generate a codingindex. If the pulse to be encoded includes a sign, the index combiningunit 33 further combines sign index information S(N) corresponding toeach position with a pulse into the coding index, where the sign indexindicates the pulse sign information of the positions with a pulsecorresponding to the sign index.

When the pulses are encoded according to the coding index structureprovided in the fifth embodiment, the index combining unit 33 mayinclude: (1) a first combining unit 331, adapted to output the secondindex and the third index combined into I23, namely, I23=I3×W(N)+I2,where W(N) represents the total quantity of all possible distributionsof the positions with a pulse on the track, and N represents thequantity of positions with a pulse corresponding to the first index; and(2) a second combining unit 332, adapted to: overlay the output of thefirst combining unit 331 with information about other indices, andoutput the coding index Index(

).

The coding apparatus disclosed in this embodiment is applicable to thecoding methods disclosed in the fifth embodiment and the sixthembodiment.

Embodiment 16

A decoder 40 is disclosed in the sixteenth embodiment. As shown in FIG.16, the decoder includes: (1) a receiving unit 41, adapted to receive acoding index Index(

); (2) a distribution extracting unit 42, adapted to extract thedistribution index I4 from the Index(

) received by the receiving unit 41; (3) a distribution decoding unit43, adapted to determine the distribution of each position with a pulseon the track according to the distribution index 14 extracted by thedistribution extracting unit 42, where the distribution is representedby Q(

); and (4) a distribution reconstructing unit 44, adapted to reconstructthe pulse order on the track according to the Q(

) determined by the distribution decoding unit 43, where Q(

) represents the distribution of each position of the pulses on thetrack.

If the pulse to be decoded includes a sign, the decoder needs to furtherinclude a sign extracting unit 45, adapted to extract the sign index SS(

) corresponding to each pulse from the Index(

) received by the receiving unit 31 according to the total quantity (

) of pulses to be encoded on the same track, where the sign indexindicates the pulse sign information of the pulse corresponding to thesign index.

In this case, the distribution reconstructing unit 44 further recoversthe positive or negative feature of the pulse sign of each pulseaccording to the pulse sign information indicated by the SS(

) extracted by the sign extracting unit 45.

Embodiment 17

The decoding apparatus disclosed in this embodiment is applicable to thedecoding methods disclosed in the seventh embodiment and the eighthembodiment.

The seventeenth embodiment provides a decoder 50. As shown in FIG. 17,the decoder includes: a first decoding module 51, a second decodingmodule 52, and a decoding selecting unit 53.

The decoding selecting unit 53 is adapted to: determine the totalquantity (

) of pulses encoded on the same track by the received coding indexIndex(

), and select a decoding mode according to N the total quantity.Optional decoding modes in this embodiment include a first decoding modeand a second decoding mode. Depending on the result of selecting thedecoding mode, the first decoding module 51 is triggered to performdecoding if the first decoding mode is selected; or the second decodingmodule 52 is triggered to perform decoding if the second decoding modeis selected.

The first decoding module 51 includes a distribution extracting unit512, a distribution decoding unit 513, a distribution reconstructingunit 514, and a sign extracting unit 515. The logical structure of suchunits is the same as that of the counterpart units in the 16thembodiment.

The second decoding module 52 includes: (1) a first extracting unit 521,adapted to: receive the coding index Index(

), extract the first index I1 from the Index (

), and determine the quantity (

) of positions with a pulse according to the I1; and (2) a secondextracting unit 522, adapted to extract the second index I2 and thethird index I3 from the coding index Index(

).

If the coding index structure is provided in the second coding mode inthe third embodiment, the second extracting unit 522 for decoding mayinclude: (1) a separating subunit 5221, adapted to extract thecombination value I23 of the second index and the third index from thecoding index; (2) a resolving subunit 5222, adapted to separate andoutput the second index I2 and the third index I3 in the following way:

I2=I23% W(N),I3=Int[I23/W(N)],

where W(N) represents the total quantity of all possible distributionsof the positions with a pulse on the track, N represents the quantity ofthe positions with a pulse corresponding to the first index, % refers totaking the remainder, and Int refers to taking the integer; (a) a firstdecoding unit 523, adapted to determine the P(N) according to the secondindex I2 with respect to the quantity of the positions with a pulsecorresponding to the I1, where P(N) represents the distribution of thepositions with a pulse on the track; (b) a second decoding unit 524,adapted to determine the SU(N) according to the third index I3, whereSU(N) represents the quantity of pulses in each position with a pulse;and (3) a pulse reconstructing unit 525, adapted to reconstruct thepulse order on the track according to the P(N) and the SU(N), where:P(N) represents distribution of the positions with a pulse on the track,and SU(N) represents the quantity of pulses in each position with apulse.

If the pulse to be decoded includes a sign, the decoder needs to furtherinclude a third extracting unit 526, adapted to extract the sign indexs(n) corresponding to each position with a pulse from the Index(

) according to the quantity (N) of the positions with a pulse, where thesign index indicates the pulse sign information of the position with apulse corresponding to the sign index.

In this case, the pulse reconstructing unit 525 may include: (1) a firstreconstructing unit 5251, adapted to recover the positive or negativefeature of the pulse sign of each position with a pulse according to theP(N) and the s(n), where P(N) represents distribution of the positionswith a pulse on the track, and s(n) represents the sign indexcorresponding to each position with a pulse; and (2) a secondreconstructing unit 5252, adapted to reconstruct the pulse order on thetrack according to the distribution of the positions with a pulse andsigns output by the first reconstructing unit 5251, and according to theSU(N) which represents the quantity of pulses in each position with apulse.

The decoding apparatus disclosed in this embodiment is applicable to thedecoding methods disclosed in the ninth embodiment and the 10thembodiment.

Embodiment 18

A decoder 60 is disclosed in the eighteenth embodiment. As shown in FIG.18, the decoder includes: (1) a first extracting unit 61, adapted to:receive the coding index Index(

), extract the first index I1 from the Index(

), and determine the quantity (N) of positions with a pulse according tothe I1; and (2) a second extracting unit 62, adapted to extract thesecond index I2 and the third index I3 from the coding index Index(

).

In the case of decoding the coding index structure provided in the fifthembodiment, the second extracting unit 62 may include: (1) a separatingsubunit 621, adapted to extract the combination value I23 of the secondindex and the third index from the coding index; (2) a resolving subunit622, adapted to separate and output the second index I2 and the thirdindex I3 in the following way:

I2=I23% W(N),I3=Int[I23/W(N)],

where W(N) represents the total quantity of all possible distributionsof the positions with a pulse on the track, N represents the quantity ofpositions with a pulse corresponding to the first index, % refers totaking the remainder, and Int refers to taking the integer; (a) a firstdecoding unit 63, adapted to determine the P(N) according to the secondindex I2 with respect to the quantity of the positions with a pulsecorresponding to the I1, where P(N) represents the distribution of thepositions with a pulse on the track; (b) a second decoding unit 64,adapted to determine the SU(N) according to the third index I3, whereSU(N) represents the quantity of pulses in each position with a pulse;and (3) a pulse reconstructing unit 65, adapted to reconstruct the pulseorder on the track according to the P(N) and the SU(N), where: P(N)represents distribution of the positions with a pulse on the track, andSU(N) represents the quantity of pulses in each position with a pulse.

If the pulse to be decoded includes a sign, the decoder needs to furtherinclude a third extracting unit 66, adapted to extract the sign indexs(n) corresponding to each position with a pulse from the Index(

) according to the quantity (N) of the positions with a pulse, where thesign index indicates the pulse sign information of the position with apulse corresponding to the sign index.

In this case, the pulse reconstructing unit 65 may include: (1) a firstreconstructing unit 651, adapted to recover the positive or negativefeature of the pulse sign of each position with a pulse according to theP(N) and the s(n), where: P(N) represents distribution of the positionswith a pulse on the track, and s(n) represents the sign indexcorresponding to each position with a pulse; and (2) a secondreconstructing unit 652, adapted to reconstruct the pulse order on thetrack according to the distribution of the positions with a pulse andsigns output by the first reconstructing unit 651, and according to theSU(N) which represents the quantity of pulses in each position with apulse.

The decoding apparatus disclosed in this embodiment is applicable to thedecoding methods disclosed in the eleventh embodiment and the twelfthembodiment.

In order to further clarify the foregoing embodiments, coding anddecoding examples are given below, where the coding is based on thecoding method in the third embodiment (the first coding mode is based onthe calculation method in the second embodiment, and the second codingmode is based on the calculation method in the fourth embodiment), andthe decoding is based on the decoding method in the ninth embodiment(the first decoding mode is based on the calculation method in theeighth embodiment, and the second decoding mode is based on thecalculation method in the 10^(th) embodiment), supposing that theselection condition of the first coding/decoding mode is:

=3, 4, 5; and the total quantity of positions on the track is M=16.

Example 1

Coding and decoding for pulse search results.

A. Coding

-   -   (1)        =6, the second coding mode is determined for the coding, and the        Index(        ) needs to occupy 21 bits.    -   (2) Statistics of N, P(N), SU(N), and S(N) are collected.    -   N=1;    -   P(1)={p(0)}={2};    -   SU(1)={su(0)}={6}; and    -   S(1)={s(0)}={0}.    -   (3) I1, I2, I3, and I23 are encoded.    -   According to N=1, it is determined that I1=0x1F0000 by reference        to FIG. 5.    -   According to the calculation method in the fourth embodiment,        I2=2.    -   Class(1)=1, I3=0, and therefore, I23=I2=2.    -   (4) The Index(        ) is generated.

$\begin{matrix}{{{Index}()} = {{I\; 1} + {I\; 23 \times 2^{}} + {{s(0)} \times 2^{ - 1}} + {{s(1)} \times 2^{ - 2}} + \ldots \; + {s\left( { - 1} \right)}}} \\{= {{0 \times 1F\; 0000} + {2 \times 2} + 0}} \\{= {0 \times 1F\; 0004}}\end{matrix}$

B. Decoding

-   -   (1) Index(        )=0x1F0004 is received.        =6 is determined according to the coding length, and the second        decoding mode is determined for decoding.    -   (2) I1, s(n), and I23 are extracted.    -   According to Index(        )=0x1F0004, it is determined that I1=0x1F0000 and N=1 by        reference to FIG. 5.    -   According to N=1, the last bit of Index(        ) is separated, and s(0)=0.    -   I23 is separated, I23=[Index(        )>>1]−I1=2, and “>>k” represents k bits shifted leftward.    -   (3) I23 is decoded.    -   according to N=1, W(1)=C₁₆ ¹=16.    -   I3=Int[I23/W(1)]=0, and unique instance corresponding to SU(1)        is SU(1)={6}.    -   I2=I23% W(1)=2; according to the calculation method in the        eighth embodiment, P(1)={p(0)}={2}.    -   (4) The pulse order is recovered.    -   According to P(1)={2}, SU(1)={6}, and s(0)=0, it is determined        that 6 positive pulses exist in position 2. The decoding process        is completed.

Example 2

-   -   Coding and decoding for pulse search results.

A. Coding

-   -   (1)        =5, the first coding mode is determined for the coding, and the        Index(        ) needs to occupy 19 bits.    -   (2) Statistics of Q(        ) and SS(        ) are collected.    -   Q(5)={q(0), q(1), q(2), q(3), q(4)}={1, 1, 4, 6, 6}; and    -   SS(5)={ss(0), ss(1), ss(2), ss(3), ss(4)}={0, 0, 0, 0, 0}.    -   (3) I4 is encoded.    -   According to the calculation method in the second embodiment,        I4=C₂₀ ⁵−C₂₀₋₁ ⁵+C₁₉₋₁ ⁴−C₁₉₋₁ ⁴+C₁₈₋₁ ³−C₁₈₋₄ ³+C₁₇₋₄ ²−C₁₇₋₆        ²+C₁₆₋₆ ¹−C₁₆₋₆ ¹=4215.    -   (4) The Index(        ) is generated.

$\begin{matrix}{{{Index}(5)} = {{I\; 4 \times 2^{5}} + {{{ss}(0)} \times 2^{4}} + {{{ss}(1)} \times 2^{4}} + \ldots \; + {{ss}(4)}}} \\{= {{4215 \times 2^{5}} + 0}} \\{= {0 \times 20\; {EE}\; 0}}\end{matrix}$

B. Decoding

-   -   (1) Index(        )=0x20EE0 is received.        =5 is determined according to the coding length, and the first        decoding mode is determined for decoding.    -   (2) Q(        ) and SS(        ) are extracted.    -   According to        =5, the last five bits of Index(        ) are separated, and ss(0)-ss(4)=0.    -   I4 is separated. I4=[Index(        )>>5]=4215.    -   (3) I4 is decoded.    -   According to the calculation method in the eighth embodiment,        Q(5)={1, 1, 4, 6, 6}.    -   (4) The pulse order is recovered.    -   According to Q(5)={1, 1, 4, 6, 6} and ss(0)˜ss(4)=0, it is        determined that 2 positive pulses exist in position 1; 1        positive pulse exists in position 4; and 2 positive pulses exist        in position 6. The decoding process is completed.

The foregoing embodiments reveal that: The pulses to be encoded areordered according to the distribution of the positions of the pulses onthe track before coding, thus simplifying the calculation; because thecoding is performed according to the order, all pulse distributionscorrespond to continuous coding, thus minimizing the coding redundancyand saving the coding bits. Further, the first coding/decoding mode isintegrated with the second coding/decoding mode under the presentinvention. Therefore, the merits of the two coding modes with differentN values complement each other, and the merits are more noticeable.

More coding and decoding examples are given below, where the coding isbased on the coding method in the second embodiment and the decoding isbased on the decoding method in the fourth embodiment, supposing thatthe total quantity of positions on the track is M=16.

Example 1

-   -   Coding and decoding for pulse search results.

A. Coding

-   -   (1)        =6, and the Index(        ) needs to occupy 21 bits.    -   (2) Statistics of N, P(N), SU(N), and S(N) are collected.    -   N=1;    -   P(1)={p(0)}={2};    -   SU(1)={su(0)}={6}; and    -   S(1)={s(0)}={0}.    -   (3) I1, 12, I3, and I23 are encoded.    -   According to N=1, it is determined that I1=0x1F0000 by reference        to FIG. 5.    -   According to the calculation method in the sixth embodiment,        I2=2.    -   Class(1)=1, I3=0, and therefore, I23=I2=2.    -   (4) The Index(        ) is generated.

$\begin{matrix}{{{Index}()} = {{I\; 1} + {I\; 23 \times 2^{}} + {{s(0)} \times 2^{ - 1}} + {{s(1)} \times 2^{ - 2}} + \ldots \; + {s\left( { - 1} \right)}}} \\{= {{0 \times 1F\; 0000} + {2 \times 2} + 0}} \\{= {0 \times 1F\; 0004}}\end{matrix}$

B. Decoding

-   -   (1) Index(        )=0x1F0004 is received.        =6 is determined according to the coding length.    -   (2) I1, s(n), and I23 are extracted.    -   According to Index(        )=0x1F0004, it is determined that I1=0x1F0000 and N=1.    -   According to N=1, the last bit of Index(        ) is separated, and s(0)=0.    -   I23 is separated, I23=[Index(        )>>1]−I1=2, and “>>k” represents k bits shifted leftward.    -   (3) I23 is decoded.    -   According to N=1, W(1)=C₁₆ ¹=16.    -   I3=Int[I23% W(1)]=0, and unique instance corresponding to SU(1)        is SU(1)={6}.    -   I2=I23% W(1)=2; according to the calculation method in the 12th        embodiment, P(1)={p(0)}={2}.    -   (4) The pulse order is recovered.    -   According to P(1)={2}, SU(1)={6}, and s(0)=0, it is determined        that 6 positive pulses exist in position 2. The decoding process        is completed.

Example 2

-   -   Coding and decoding for pulse search results.

A. Coding

-   -   (1)        =6, and the Index(        ) needs to occupy 21 bits.    -   (2) Statistics of N, P(N), SU(N), and S(N) are collected.    -   N=2;    -   P(2)={p(0), p(1)}={2, 4};    -   SU(2)={su(0), su(1)}={2, 4}; and    -   S(2)={s(0), s(1)}={0, 0}.    -   (3) I1, I2, I3, and I23 are encoded.    -   According to N=2, it is determined that I1=0x1E0000 by reference        to FIG. 5.    -   According to the calculation method in the sixth embodiment,        I2=30.    -   Considering Class(2)=5, supposing that five possible instances        of SU(2) are arranged in this order: {{5, 1}, {4, 2}, {3, 3},        {2, 4}, and {1, 5}}, then SU(2)={2, 4} is the fourth instance,        and 13=3, and therefore, I23=I3×C₁₆ ²+I2=390.    -   (4) The Index(        ) is generated.

$\begin{matrix}{{{Index}()} = {{I\; 1} + {I\; 23 \times 2N} + {{s(0)} \times 2N} - 1 + {{s(1)} \times 2N} - 2 + \ldots \; + {s\left( {N - 1} \right)}}} \\{= {{0 \times 1E\; 0000} + {390 \times 4} + 0 + 0}} \\{= {0 \times 1E\; 0618}}\end{matrix}$

B. Decoding

-   -   (1) Index(        )=0x1E0618 is received.        =6 is determined according to the coding length.    -   (2) I1, s(n), and I23 are extracted.    -   According to Index(        )=0x1E0618, it is determined that I1=0x1E0000 and N=2 by        reference to FIG. 5.    -   According to N=2, the last two bits of Index(        ) are separated, s(0)=0, and s(1)=0.    -   I23 is separated. I23=[Index(        )>>2]−I1=390.    -   (3) I23 is decoded.    -   According to N=2, W(2)=C₁₆ ²=120.    -   I3=Int[I23/W(2)]=3. According to the order of all the same        instances of SU(2) applied at the coder, the fourth instance is        matched: SU(2)={2, 4}.    -   I2=I23% W(2)=30; according to the calculation method in the 12th        embodiment, P(2)={2, 4}.    -   (4) The pulse order is recovered.

According to P(2)={2, 4}, SU(2)={2, 4}, s(0)=0, and s(1)=0, it isdetermined that 2 positive pulses exist in position 2; and 4 positivepulses exist in position 4. The decoding process is completed.

The foregoing embodiments reveal that: The pulses to be encoded arecombined according to positions, and the quantity of positions with apulse, distribution of the positions with a pulse on the track, and thequantity of pulses in each position with a pulse are encoded. To anyquantity of pulses to be encoded, the coding method under the presentinvention is uniformly applicable, thus avoiding increase of the codingindex redundancy caused in the recursive mode, and ensuring a highutilization ratio of the coding bits. Meanwhile, it is not necessary toencode multiple pulses in the same position separately. Instead, thepositions of pulses are merged before coding, thus saving coding bits.With the increase of the pulses to be encoded on the track, theprobability of overlaying pulse positions also increases, and the meritsof the embodiments of the prevent invention are more noticeable.

Detailed above are a coding method, a decoding, a coder, and a decoderunder the present invention. Although the invention is described throughsome exemplary embodiments, the invention is not limited to suchembodiments. It is apparent that those skilled in the art can makevarious modifications and variations to the invention without departingfrom the spirit and scope of the invention. The invention is intended tocover the modifications and variations provided that they fall in thescope of protection defined by the following claims or theirequivalents.

What is claimed is:
 1. A method for coding, comprising: obtaining apulse distribution of the pulses to be encoded on a track, wherein thepulse distribution includes quantity of pulse positions, distribution ofpulse positions on the track, and quantity of pulses in each pulseposition; determining a first index according to the quantity of thepulse positions, wherein the first index corresponds to all possibledistributions of the pulse positions on the track when the quantity ofpulse positions is determined; determining a second index according tothe distribution of pulse positions on the track, wherein the secondindex corresponds to a distribution, corresponding to a distribution ofcurrent pulse position, of the all possible distributions of the pulsepositions corresponding to the first index; determining a third indexaccording to the quantity of pulses in each pulse position, wherein thethird index corresponds to the quantity of pulses in each pulseposition; and generating a coding index that includes the first index,the second index, and the third index.
 2. The method of claim 1, whereinfurther comprising: permuting the all possible distributions of thepulse positions on the track in a set order with respect to the currentquantity of pulses before determining the second index according to thedistribution of pulse positions on the track, wherein the permutingnumber in the permutation serves as a distribution index indicative ofthe corresponding distribution.
 3. The method of claim 1, wherein themethod further comprises: obtaining pulse sign information indicative ofthe positive and negative features of the pulses when obtaining thepulse distribution on a track; and determining a pulse sign indexcorresponding to the pulse sign information after determining the thirdindex, the coding index further comprises the pulse sign indexcorresponding to each pulse.
 4. The method of claim 1, whereingenerating a coding index comprises: overlaying information about otherindices with the first index used as a start value, a value of the firstindex corresponds to an independent value range of the coding index,when overlaying the information about other indices with the first indexused as the start value overlaying the combination of the second indexand the third index in following way,I3×W(N)+I2; wherein I2 represents the second index, I3 represents thethird index, W(N) represents total quantity of all possibledistributions of the pulse positions on the track, and N represents thequantity of the pulse positions corresponding to the first index.
 5. Acoding device comprising a processor and a nonvolatile memory where aset of instruction is stored, and the instruction is executed by theprocessor to performing the following: obtaining a pulse distribution,of the pulses to be encoded on a track, wherein the pulse distributionincludes quantity of pulse positions, distribution of pulse positions onthe track, and quantity of pulses in each pulse position; determining afirst index according to the quantity of the pulse positions, whereinthe first index corresponds to all possible distributions of the pulsepositions on the track when the quantity of pulse positions isdetermined; determining a second index according to the distribution ofpulse positions on the track, wherein the second index corresponds to adistribution, corresponding to a distribution of current pulse position,of the all possible distributions of the pulse positions correspondingto the first index; determining a third index according to the quantityof pulses in each pulse position, wherein the third index corresponds tothe quantity of pulses in each pulse position; and generating a codingindex that includes the first index, the second index, and the thirdindex.
 6. The coding device of claim 5, wherein further comprising:permuting the all possible distributions of the pulse positions on thetrack in a set order with respect to the current quantity of pulsesbefore determining the second index according to the distribution ofpulse positions on the track, wherein the permuting number in thepermutation serves as a distribution index indicative of thecorresponding distribution.
 7. The coding device of claim 5, wherein themethod further comprises: obtaining pulse sign information indicative ofthe positive and negative features of the pulses when obtaining thepulse distribution on a track; and determining a pulse sign indexcorresponding to the pulse sign information after determining the thirdindex, the coding index further comprises the pulse sign indexcorresponding to each pulse.
 8. The coding device of claim 5, whereingenerating a coding index comprises: overlaying information about otherindices with the first index used as a start value, a value of the firstindex corresponds to an independent value range of the coding index,when overlaying the information about other indices with the first indexused as the start value overlaying the combination of the second indexand the third index in following way,I3×W(N)+I2; wherein I2 represents the second index, I3 represents thethird index, W(N) represents total quantity of all possibledistributions of the pulse positions on the track, and N represents thequantity of the pulse positions corresponding to the first index.